(CNN) - Rudy Giuliani is the star of a new robocall from the McCain campaign and the Republican National Committee that seeks to portray Barack Obama as soft on crime.

In the new call, to be blasted to voters in several swing states, the former federal prosecutor and New York City mayor says Obama opposes "mandatory prison sentences for sex offenders, drug dealers, and murderers."

"You need to know that Barack Obama opposes mandatory prison sentences for sex offenders, drug dealers, and murderers," Giuliani says in the call. "It's true, I read Obama's words myself. And recently, congressional liberals introduced a bill to eliminate mandatory prison sentences for violent criminals - trying to give liberal judges the power to decide whether criminals are sent to jail or set free."

"With priorities like these, we just can't trust the inexperience and judgment of Barack Obama and his liberal allies," Giuliani says.

The Obama campaign did not have an immediate comment, but according to its Web site, the Illinois senator does support "reforming mandatory minimum prison sentences."

"Every leading expert body in criminal justice has opposed the use of mandatory minimum sentences, including the Sentencing Commission, the Judicial Conference, the American Bar Association, and leading criminal justice scholars," his Web site ways.

Giuliani's robocall comes a week after the Republican National Committee and the McCain campaign blasted a robocall to swing-state voters highlighting the Democratic presidential candidate's connection to 1960's radical William Ayers.

Those calls have drawn criticism from a handful of vulnerable Senate Republicans wary of turning off independent voters, including Maine's Susan Collins, Minnesota's Norm Coleman and Oregon's Gordon Smith.